Worse Prognosis Found for Obese, Underweight Myeloma Patients
New study links BMI extremes to higher risk of death, worse cancer
Extremes in body mass index (BMI) — a ratio of weight to height that’s used to estimate a person’s healthy weight — are associated with a worse prognosis among people with multiple myeloma, according to data from more than 1,000 patients.
Specifically, underweight and severely obese patients experienced a shorter time to disease progression or death than those with a normal BMI, or who were overweight or moderately obese.
Moreover, underweight patients were found to have a two times higher risk of death compared with other groups.
“Clinical research to understand if patients with extreme BMI may benefit from weight management strategies to improve outcomes may be of importance,” the researchers wrote.
The findings, “Extreme body mass index and survival in newly diagnosed multiple myeloma patients,” were published as a correspondence to the editor in the Blood Cancer Journal.
Examining BMI impact on disease prognosis
Most risk factors for a poor prognosis in multiple myeloma — such as age or genetic status — are non-modifiable, meaning they cannot be targeted as a way of altering the disease course.
“There is a lack of evidence-based clinical interventions available to complement existing treatment modalities to improve prognostic trajectories,” the researchers wrote.
For multiple myeloma development, obesity has been identified as a potentially modifiable risk factor. However, its potential role in predicting clinical outcomes after a diagnosis remains largely unclear. Additionally, there is scant research into the impact of being underweight.
A previous study evaluated whether BMI at the time of a multiple myeloma diagnosis was associated with long-term outcomes among nearly 3,000 patients treated through the U.S. Veterans Health Administration System.
Results showed that underweight patients had increased mortality, while obese patients exhibited better survival rates, except for those who had lost a significant amount of weight in the year before diagnosis.
Now, a team led by researchers in the U.S. sought to learn more. They investigated the impact of BMI on prognosis by analyzing data from 1,120 newly diagnosed multiple myeloma patients included in the Multiple Myeloma Research Foundation’s CoMMpass registry (NCT01454297).
CoMMpass is an observational study that follows multiple myeloma patients every six months until death or last available follow-up.
The focus of this analysis was progression-free survival, or the time until disease progression or death occurs, as well as overall survival.
The newly diagnosed patients were comprised of 61% men and 39% women, mostly white (66%), and with a median age of 63.
Of the included participants, 2% were underweight, with a BMI of less than 18.5, and 30% had a normal weight, with a BMI between 18.5–24.
The majority of patients were at the other end of the scale: 38.2% were overweight, with a BMI between 25–29, 17.9% were moderately obese, with a BMI between 30–34, and 11.9% were severely obese, with a BMI of 35 or above.
Worse prognosis for underweight, severely obese patients
Severely obese patients were significantly younger at the time of their diagnosis than those in the other groups (61 vs. 63–64 years). Male patients were more likely to be overweight or obese compared with female patients (73.5% vs. 59.5%), whereas women were more likely to be underweight (3.6% vs. 0.88%).
White and Black patients were more likely to have a higher than normal BMI compared with other races.
Eastern Cooperative Oncology Group (ECOG) performance status, a measure of a cancer patient’s daily functioning, differed by weight group. Specifically, underweight and severely obese patients were more likely to have a higher ECOG score, reflecting a worse functional status.
Over a median follow-up of more than two years, underweight and severely obese patients had a lower median time to disease progression or death compared with normal, overweight, and moderately obese patients.
Final statistical analyses, adjusted for clinical factors that could influence the outcome, showed that underweight patients were at a significantly higher risk of death, by about 2.3 times.
“We speculate that the observed adverse outcomes in this subgroup maybe due to high ECOG (i.e., poor performance status) and disease-related weight loss,” the researchers wrote.
Severely obese patients showed an elevated risk of both disease progression and death, but these findings did not reach statistical significance.
This potentially higher risk could be due to an increased number of fat cells, which provide a favorable environment for myeloma growth, the team suggested, noting that it also could be due to a worse ECOG status.
This comprehensive examination of BMI and survival in newly diagnosed [multiple myeloma] patients suggests that underweight and severe obesity are associated with worse survival.
Other measures of risk status were evaluated. The Charlson Comorbidity Index (CCI) assesses the presence and severity of simultaneous health conditions to predict a person’s mortality risk, with higher scores reflecting greater risk status.
ECOG scores, CCI scores, and age were then used to determine a person’s overall frailty, or reduced health or strength that is associated with higher vulnerability to poor outcomes.
Survival rates were significantly lower among patients with higher CCI scores compared with those with lower scores (65% vs. 87%), and among frail patients compared with non-frail patients (70% vs. 88%).
“This comprehensive examination of BMI and survival in newly diagnosed [multiple myeloma] patients suggests that underweight and severe obesity are associated with worse survival,” the researchers wrote, adding that “future studies of weight trajectories and body composition may help clarify these observations.”